Natural and conglomerated stone elements are widely used in the construction industry, with applications varying from flooring and wall panelling to kitchen and counter-tops etc. One of the major flaws of some natural- and conglomerated flat stone elements, especially those comprising marble or other calcium carbonate based stone types, is their relative low resistance to scratch, wear, chemical attack and UV attack.
Many proposals have been made to protect natural and agglomerated stone plate-like elements.
DE-A-102004023153, proposes a method of applying a protective layer of boron silica glass adhered via adhesive layer to a surface or base of a natural or cast stone structural member. This invention provides a solution for both wear as chemical resistance of natural or cast stone surfaces, but the solution to apply a thin layer of boron silica glass is significantly different from the solution provided in the proposed invention and does not provide similar benefits.
U.S. Pat. No. 6,205,727 proposes the application of a reinforcing layer to the visible face of slabs of stone material. For slabs of marble and granite, especially thin slabs, the reinforcing layer is constituted by non-twisted glass threads, preferably in the form of a mat, and by a transparent resin resistant to the action of atmospheric and chemical agents. A reinforced slab is obtained which has a small thickness and in which the resistance to negative flexing is greatly increased, along a front face concomitantly with the resistance to positive flexing along the rear, or invisible, face of the slab when the rear face is also reinforced. This invention also mentions the use of extremely fine glass of quartz powder in order to increase the scratch or abrasion resistance. Epoxy and or acrylic resins supplemented with UV ray absorbers and or so called UV ray scavengers are mentioned to increase the UV resistance of the finished product.
Wear resistant surface protection layers are widely used in the laminating industry, we can mention among others U.S. Pat. Nos. 3,663,341, 3,756,901, 4,255,480, DE-A-2107091. US-A-2008/0014343 describes an enhanced scratch resistance of articles such as wood-based articles or a surface of an automobile, including a nano-particle-based additive and discloses a film forming composition comprising a resin, a plurality of nanoparticles, a surface active material and a polymeric dispersant.
U.S. Pat. No. 6,955,834 refers to a long lasting coating for modifying hard surfaces and processes for applying the same and discloses a material for coating a hard surface said coating material comprising an effective amount of non-photoactive nanoparticles. While application of referred coating is disclosed to be suitable for stone surfaces including granite, marble, sandstone, etc., the invention mainly refers and claims an automobile body panel.
U.S. Pat. No. 6,896,958, discloses a transparent film-forming composition containing surface treated nanocristalline particles dispersed in a cross-linkable resin, providing a substantially transparent abrasion-resistant coating formed on a substrate such as with floor and countertop coverings and automotive panel.
In EP-B-1122334 a method of forming a coated body having a layer of Al2O3 is disclosed. The coating is performed by chemical vapour deposition under higher temperature and controlled atmosphere.
EP-1160283 provides a composition for use in forming an abrasion-resistant easy to clean coating on a substrate comprising a mixture of a fluorocarbon polymer component and an enamel-forming component, said enamel-forming component comprising by weight from about 15% to about 30% of Al2O3. The coating is applied mainly to a vehicle panel but use for covering ceramics and stone is also disclosed.
U.S. Pat. No. 6,896,934 concerning hybrid coating compositions refers as a conventional practice to avoid the problems to obtain a non-stick polymeric coating that adhere well to substrates such as ceramics, to apply one or more base coats containing adhesive resins in order to better adhere fluorocarbon polymer top coats to substrates. As in this antecedent in the present invention the term base coat and primer coat will be understood as having this particular meaning.
U.S. Pat. No. 5,431,962, JP61286281 and DDA3223043 disclose concrete substrates provided with a multilayered coating to protect the substrate from abrasion.
This invention provides a natural or conglomerated stone plate-like element, in particular a flat element as a tile or slab with a protective multilayered coating specially created to appropriate reinforce and protect a petrous substrate that therefore can be thinner than other plate-like elements already known in the field. Moreover the invention also offers a conglomerated stone plate-like element with a finishing in particular a wood one on an in face showing that remains sheltered by referred multilayered protective coating.